High Flow Oyxgen Therapy

Question 1

What is high flow oxygen therapy (HFOT)?

Answer 1

• Mix of O2 and air that is humidified and warmed

- Provides small amount of PEEP to decrease WOB and increase oxygenation and perfusion

Question 2

What are some common indications for HFOTin paediatrics?

Answer 2

• Acute LRTIs
  e.g. bronchiolitis, pneumonia, asthma)
• Requiring NP O2
  > 2L/min if = 2 years old
  > 4L/min if >2 years old
• Excessive WOB

Question 3

What is the mechanism of action for humidified HFOT in paediatrics patients?

Answer 3

• Reduce damage to upper airway mucosa (cold dry air causes inflammatory reactions and naso-pulmonary bronchoconstriction)
• Washout of nasopharyngeal dead space so alveolar ventilation is a greater % of minute ventilation
• Reduction of upper airway resistance (which contributes approx. 50% of total airway resistance)
• Provide a degree of CPAP to keep the child’s airway open and improve ventilation

Question 4

What are some common indications for HFOT in adults?

Answer 4

• Acute type 1 respiratory failure refractory to standard O2 therapy
  (needing >4L/min for >4 hours)

Question 5

What are some contraindications for the use of HFOT in adults?

Answer 5

• Facial abnormalities/trauma/surgery
• Altered LOC
• Epistaxis

Question 6

What is the mechanism of action for humidified HFOT in adult patients?

Answer 6

• ^ and stabilises FiO2
• Decreases anatomical dead space
• May generate PAP
• ^ H2O content of mucous, reducing sputum retention
• ^ patient comfort and tolerance

Question 7

What are some contraindications for use of HFOT in paediatrics?

Answer 7

• Cardiac cause of increased WOB/hypoxia
• Air leak (e.g. pneumothorax)
• Facial trauma/abnormality/surgery